Backend Development
PHP Tutorial
PHP optimistic locking combined with transaction deduction balance failed: How to ensure that the balance is correctly deducted in concurrency situations?
PHP optimistic locking combined with transaction deduction balance failed: How to ensure that the balance is correctly deducted in concurrency situations?
Mar 31, 2025 pm 11:42 PM
PHP Optimistic Locking Combined with Database Transactions to Deduct Balance: Problem Analysis and Solution
This article discusses how to avoid concurrency problems that lead to failure of balance deduction or inconsistent data when using optimistic locks and database transactions for balance deduction in PHP environment. We will analyze the error code and provide the correct solution.
Problem code analysis and error reasons:
The following code snippet attempts to ensure the correctness of balance deductions in concurrent environments through optimistic locks and transactions, but has flaws:
Error code snippet 1:
public function userbuy()
{
$user = $this->getuser();
$oldmoney = $user['balance'];
$orderoffer = $this->getordermoney($orderid);
if($oldmoney error('Insufficient Account Balance');
//Optimistic locking solution (wrong points)
$newmoney = $oldmoney - $orderoffer['price'];
$newuser = smsuser::where(['id' => $user['id'],'balance' => $oldmoney])->find();
if(!$newuser) $this->error('user does not exist');
//Open database transaction db::transaction(function () use($newuser,$orderid,$newmoney){
$newuser->balance = $newmoney;
$result = $newuser->save();
if(!$result) $this->error('Save balance failed');
//Create an order code
//Deduct inventory code
//Create user balance change record code
db::commit(); //Commit transaction (excessive operation)
});
}
Cause of error:
Optimistic lock position error:
find()method is executed outside the transaction. Multiple concurrent requests get the same$oldmoneyvalue. Onlysave()operation of the first request succeeds, and subsequent requests fail becausebalanceis no longer equal to$oldmoney. The conditional judgment of optimistic locking should be made inupdatestatement.db::commit()redundant:db::transaction()method itself will automatically commit the transaction unless an exception rollback occurs. Manual call todb::commit()is redundant and may mask errors.
Error code snippet 2:
public function userbuy()
{
// ... (The code is the same as above, the part is omitted) ...
//Optimistic locking solution (wrong points)
$newUser->balance = $newMoney;
$result = $newUser->save();
if(!$result) $this->error('Save balance failed');
//Open database transaction (Error)
Db::transaction(function() use(){
//Create an order code
//Deduct inventory code
//Create user balance change record code
Db::commit(); //Commit transaction (excessive operation)
});
}
Cause of error:
The balance update operation is executed outside the transaction. If subsequent operations (creating orders, deducting inventory, etc.) fail, the balance has been updated, resulting in inconsistent data.
Correct solution:
The conditional judgment of optimistic locking should be placed in the database update statement, and all operations that need to ensure atomicity should be included in the same transaction.
Correct code:
public function userbuy()
{
$user = $this->getuser();
$oldmoney = $user['balance'];
$orderoffer = $this->getordermoney($orderid);
if ($oldmoney error('Insufficient Account Balance');
$newmoney = $oldmoney - $orderoffer['price'];
// Use optimistic locking mechanisms for databases (such as MySQL)
$affectedRows = smsuser::where('id', $user['id'])
->where('balance', $oldmoney)
->update(['balance' => $newmoney]);
if ($affectedRows === 0) {
$this->error('Balance update failed, there may be concurrent conflict'); // Optimistic lock failed return;
}
// Enable the transaction, including all subsequent operations db::transaction(function () use ($orderid, $newmoney, $user) {
// Create an order code
// Deduct inventory code
// Create user balance change record code (make sure these operations are also included in the transaction)
});
}
This solution places balance updates and subsequent operations in the same transaction and uses the optimistic locking mechanism provided by the database to ensure data consistency. If any operation fails, the transaction will automatically roll back to ensure data security. Avoid manually committing transactions, simplifying code and improving readability. If the number of rows affected by the update statement is 0, it means that the optimistic lock fails and concurrent conflicts need to be handled. Such situations can be handled using retry mechanisms or other strategies. The specific optimism lock implementation depends on the database system used.
The above is the detailed content of PHP optimistic locking combined with transaction deduction balance failed: How to ensure that the balance is correctly deducted in concurrency situations?. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undress AI Tool
Undress images for free
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
How to use PHP to combine AI to generate image. PHP automatically generates art works
Jul 25, 2025 pm 07:21 PM
PHP does not directly perform AI image processing, but integrates through APIs, because it is good at web development rather than computing-intensive tasks. API integration can achieve professional division of labor, reduce costs, and improve efficiency; 2. Integrating key technologies include using Guzzle or cURL to send HTTP requests, JSON data encoding and decoding, API key security authentication, asynchronous queue processing time-consuming tasks, robust error handling and retry mechanism, image storage and display; 3. Common challenges include API cost out of control, uncontrollable generation results, poor user experience, security risks and difficult data management. The response strategies are setting user quotas and caches, providing propt guidance and multi-picture selection, asynchronous notifications and progress prompts, key environment variable storage and content audit, and cloud storage.
PHP realizes commodity inventory management and monetization PHP inventory synchronization and alarm mechanism
Jul 25, 2025 pm 08:30 PM
PHP ensures inventory deduction atomicity through database transactions and FORUPDATE row locks to prevent high concurrent overselling; 2. Multi-platform inventory consistency depends on centralized management and event-driven synchronization, combining API/Webhook notifications and message queues to ensure reliable data transmission; 3. The alarm mechanism should set low inventory, zero/negative inventory, unsalable sales, replenishment cycles and abnormal fluctuations strategies in different scenarios, and select DingTalk, SMS or Email Responsible Persons according to the urgency, and the alarm information must be complete and clear to achieve business adaptation and rapid response.
How to use PHP to develop a Q&A community platform Detailed explanation of PHP interactive community monetization model
Jul 23, 2025 pm 07:21 PM
1. The first choice for the Laravel MySQL Vue/React combination in the PHP development question and answer community is the first choice for Laravel MySQL Vue/React combination, due to its maturity in the ecosystem and high development efficiency; 2. High performance requires dependence on cache (Redis), database optimization, CDN and asynchronous queues; 3. Security must be done with input filtering, CSRF protection, HTTPS, password encryption and permission control; 4. Money optional advertising, member subscription, rewards, commissions, knowledge payment and other models, the core is to match community tone and user needs.
How to set environment variables in PHP environment Description of adding PHP running environment variables
Jul 25, 2025 pm 08:33 PM
There are three main ways to set environment variables in PHP: 1. Global configuration through php.ini; 2. Passed through a web server (such as SetEnv of Apache or fastcgi_param of Nginx); 3. Use putenv() function in PHP scripts. Among them, php.ini is suitable for global and infrequently changing configurations, web server configuration is suitable for scenarios that need to be isolated, and putenv() is suitable for temporary variables. Persistence policies include configuration files (such as php.ini or web server configuration), .env files are loaded with dotenv library, and dynamic injection of variables in CI/CD processes. Security management sensitive information should be avoided hard-coded, and it is recommended to use.en
How to use PHP to develop product recommendation module PHP recommendation algorithm and user behavior analysis
Jul 23, 2025 pm 07:00 PM
To collect user behavior data, you need to record browsing, search, purchase and other information into the database through PHP, and clean and analyze it to explore interest preferences; 2. The selection of recommendation algorithms should be determined based on data characteristics: based on content, collaborative filtering, rules or mixed recommendations; 3. Collaborative filtering can be implemented in PHP to calculate user cosine similarity, select K nearest neighbors, weighted prediction scores and recommend high-scoring products; 4. Performance evaluation uses accuracy, recall, F1 value and CTR, conversion rate and verify the effect through A/B tests; 5. Cold start problems can be alleviated through product attributes, user registration information, popular recommendations and expert evaluations; 6. Performance optimization methods include cached recommendation results, asynchronous processing, distributed computing and SQL query optimization, thereby improving recommendation efficiency and user experience.
Securing MySQL Connections with SSL/TLS Encryption
Jul 21, 2025 am 02:08 AM
Why do I need SSL/TLS encryption MySQL connection? Because unencrypted connections may cause sensitive data to be intercepted, enabling SSL/TLS can prevent man-in-the-middle attacks and meet compliance requirements; 2. How to configure SSL/TLS for MySQL? You need to generate a certificate and a private key, modify the configuration file to specify the ssl-ca, ssl-cert and ssl-key paths and restart the service; 3. How to force SSL when the client connects? Implemented by specifying REQUIRESSL or REQUIREX509 when creating a user; 4. Details that are easily overlooked in SSL configuration include certificate path permissions, certificate expiration issues, and client configuration requirements.
How to develop AI intelligent form system with PHP PHP intelligent form design and analysis
Jul 25, 2025 pm 05:54 PM
When choosing a suitable PHP framework, you need to consider comprehensively according to project needs: Laravel is suitable for rapid development and provides EloquentORM and Blade template engines, which are convenient for database operation and dynamic form rendering; Symfony is more flexible and suitable for complex systems; CodeIgniter is lightweight and suitable for simple applications with high performance requirements. 2. To ensure the accuracy of AI models, we need to start with high-quality data training, reasonable selection of evaluation indicators (such as accuracy, recall, F1 value), regular performance evaluation and model tuning, and ensure code quality through unit testing and integration testing, while continuously monitoring the input data to prevent data drift. 3. Many measures are required to protect user privacy: encrypt and store sensitive data (such as AES
How to build an online customer service robot with PHP. PHP intelligent customer service implementation technology
Jul 25, 2025 pm 06:57 PM
PHP plays the role of connector and brain center in intelligent customer service, responsible for connecting front-end input, database storage and external AI services; 2. When implementing it, it is necessary to build a multi-layer architecture: the front-end receives user messages, the PHP back-end preprocesses and routes requests, first matches the local knowledge base, and misses, call external AI services such as OpenAI or Dialogflow to obtain intelligent reply; 3. Session management is written to MySQL and other databases by PHP to ensure context continuity; 4. Integrated AI services need to use Guzzle to send HTTP requests, safely store APIKeys, and do a good job of error handling and response analysis; 5. Database design must include sessions, messages, knowledge bases, and user tables, reasonably build indexes, ensure security and performance, and support robot memory
